The detection of drowsiness is of importance because drowsiness impairs the ability of operators of a wide range of equipment including motor vehicles, aircraft and boats as well as industrial equipment. The problem of drowsy driving cannot be solved by educating drivers to take remedial action when feeling drowsy. The difficulty is that many people are unaware of their drowsiness before and during the drowsiness even though they may be alert and aware after they rouse. This means one cannot predict when their level of drowsiness will next decrease to the point of danger because the drowsy state involves a loss of awareness of the present; an involuntary lapse of attention.
U.S. Pat. No. 5,745,038 discloses an eye monitor that examines reflected light from the eye to detect blinking behavior as an indicator of drowsiness.
U.S. Pat. No. 6,097,295 discloses a system of image analysis based on eye pupil size.
U.S. Pat. No. 6,147,612 discloses a system of preventing sleep which detects eyelid movement and actuates an alarm when the eyelid movement is indicative of drowsiness.
U.S. Pat. No. 6,346,887 uses a video based eye tracking system which tracks eye activity and pupil diameter and position to produce a signal representing eye activity that can be used to estimate alertness.
WO 03/039358 disclosed an alertness monitor that used infra red light to measure the amplitude and velocity of eyelid and eye movements to derive a measure of alertness on a scale that can be related to the scale of blood alcohol levels. This monitor sought to provide a real time alertness monitor that can provide a calibrated measure of the operator's alertness. The quality of the signals received from the light reflected off the eye and eyelid depends in part on the orientation of the emitters and detectors.
Adjustable frames for spectacles are known but generally are adjustable to accommodate the distance between the pupils and the distance between the mid point of the eyes and the bridge of the nose.
U.S. Pat. No. 5,583,586 provides a support system for spectacles which spaces the frame from the cheek bones and brow of the wearer.
Testing apparatus for examining eyes usually include fittings adjustable in several directions.
U.S. Pat. No. 4,448,501 discloses trial spectacles with means to vary the lens positions.
U.S. Pat. No. 5,499,063 discloses an adjustable nose bridge and means to move the lenses.
EP 567817 discloses trial frames which allow adjustment in the plane parallel to the face and also away from the face.
U.S. Pat. No. 4,730,898 provides a stereoscopic viewer with frames that allow the device to be adjustable in length relative to the ears.
U.S. Pat. No. 5,971,538 discloses a head mounted virtual reality display with an articulated nose bridge that allows the position of the display relative to the eyes to be adjustable.
It is an object of this invention to provide spectacles for an eye monitoring system of the type disclosed in WO 03/039358.